JSON Validator
Validate, format and minify JSON instantly.
Online JSON validator and formatter: verify and beautify your JSON instantly
JSON (JavaScript Object Notation) is the most widely used data exchange format in modern web development. Virtually all REST APIs send and receive data in JSON format, and it is the standard for configuration files in tools like package.json (Node.js), tsconfig.json (TypeScript), and many more.
Our tool offers three main functions: validation (detects syntax errors and tells you exactly what's wrong), formatting (indents JSON with 2 spaces for easier reading), and minification (removes all unnecessary spaces and line breaks to reduce file size).
All processing occurs locally in your browser through the native JSON.parse and JSON.stringify JavaScript functions. This means your data never leaves your device, which is important when working with sensitive information like API tokens, user data, or production configurations.
Frequently asked questions
What are the most common JSON errors?
The most frequent errors include: trailing commas after the last element of an object or array, using single quotes instead of double quotes, forgetting quotes around key names, comments inside JSON (not valid in standard JSON), and undefined or NaN values that don't exist in the JSON specification.
What is the purpose of minifying JSON?
Minifying JSON reduces its size by removing unnecessary spaces, tabs, and line breaks. This is useful for optimizing API responses (less bandwidth), storing data more efficiently in databases, and reducing the size of configuration files in production. A formatted JSON can weigh up to 30-40% more than its minified version.
Are JSON and JavaScript the same?
No. Although JSON was inspired by JavaScript object syntax, they are different formats. JSON is stricter: it only allows double quotes, does not support comments, does not allow functions or values like undefined. JSON is language-independent and is used with Python, Java, PHP, Go, and virtually any modern programming language.
Want to learn more? Read our complete guide →